Simplex turbopump design

Turbomachinery used in liquid rocket engines typically are composed of complex geometries made from high strength-to-weight super alloys and have long design and fabrication cycle times (3 to 5 years). A simple, low-cost turbopump is being designed in-house to demonstrate the ability to reduce the overall cost to $500K and compress life cycle time to 18 months. The simplex turbopump was designed to provide a discharge pressure of 1500 psia of liquid oxygen at 90 lbm/s. The turbine will be powered by gaseous oxygen. This eliminates the need for an inter-propellant seal typically required to separate the fuel-rich turbine gases from the liquid oxygen pump components. Materials used in the turbine flow paths will utilize existing characterized metals at 800 deg R that are compatible with a warm oxygen environment. This turbopump design would be suitable for integration with a 40 K pound thrust hybrid motor that provides warm oxygen from a tapped-off location to power the turbine. The preliminary and detailed analysis was completed in a year by a multiple discipline, concurrent engineering team. Manpower, schedule, and cost data were tracked during the process for a comparison to the initial goal. The Simplex hardware is the procurement cycle with the expectation of the first test to occur approximately 1.5 months behind the original schedule goal

The retroflection of part of the East Greenland Current at Cape Farewell

The East Greenland Current (EGC) and the smaller East Greenland Coastal Current (EGCC) provide the major conduit for cold fresh polar water to enter the lower latitudes of the North Atlantic. They flow equatorward through the western Irminger Basin and around Cape Farewell into the Labrador Sea. The surface circulation and transport of the Cape Farewell boundary current region in summer 2005 is described. The EGCC merges with Arctic waters of the EGC to the south of Cape Farewell, forming the West Greenland Current. The EGC transport decreases from 15.5 Sv south of Cape Farewell to 11.7 Sv in the eastern Labrador Sea (where the water becomes known as Irminger Sea Water). The decrease in EGC transport is balanced by the retroflection of a substantial proportion of the boundary current (5.1 Sv) into the central Irminger Basin; a new pathway for fresh water into the interior of the subpolar gyre

A Spectroscopic Orbit for Regulus

We present a radial velocity study of the rapidly rotating B-star Regulus that indicates the star is a single-lined spectroscopic binary. The orbital period (40.11 d) and probable semimajor axis (0.35 AU) are large enough that the system is not interacting at present. However, the mass function suggests that the secondary has a low mass (M_2 > 0.30 M_sun), and we argue that the companion may be a white dwarf. Such a star would be the remnant of a former mass donor that was the source of the large spin angular momentum of Regulus itself.Comment: 18 pages, 2 figures, ApJL in pres

Calibration-free regional RF shims for MRS

Purpose: Achieving a desired RF transmit field (B1+) in small regions-of-interest (ROIs) is critical for single-voxel MR spectroscopy at ultra-high field. RF shimming, using parallel transmission, requires B1+ mapping and optimisation, which limits its ease-of-use. This work aimed to generate calibration-free RF shims for pre-defined target ROIs, which can be applied to any participant, to produce a desired absolute magnitude B1+ (|B1+|).Methods: RF shims were found offline by joint-optimisation on a database, comprising B1+ maps from 11 subjects, considering ROIs in occipital cortex (OCC), hippocampus (Hippo.) and posterior-cingulate (PCC), as well as whole brain. The |B1+| achieved was compared to a tailored shimming approach, and MR spectra were acquired using tailored and calibration-free shims in 4 participants. Global and local 10g specific absorption rate (SAR) deposition were estimated using Duke and Ella dielectric models.Results: There was no difference in the mean |B1+| produced using calibration-free vs. tailored RF shimming in OCC (p=0.15), Hippo. (p=0.5) or PCC (p=0.98) although differences were observed in the root-mean-square error (RMSE) |B1+|. Spectra acquired using calibration-free shims had similar SNR and low residual water signal. Under identical power settings, SAR deposition was lower compared to operating in quadrature mode. For example, total head SAR was around 35% less for OCC.Conclusion: This work demonstrates that static RF shims, optimised offline for small regions, avoid the need for B1+ mapping and optimisation for each ROI and participant. Furthermore, power settings may be increased when using calibration-free shims to better take advantage of RF shimming

Experiencing Jobcentre Plus Pathfinders : overview of early evaluation evidence

Jobcentre Plus is a key part of the Government's strategy for welfare reform. It brings together the services of the Employment Service and parts of the Benefits Agency to provide a single point of delivery for jobs, benefits advice and support for people of working age. In the process, it aims to provide a work focus to the benefit system for everyone using the service. The first 56 Jobcentre Plus Pathfinder offices, established in October 2001, built upon the ONE service, which from June 1999 had piloted the integration of benefit claiming and work placement/job seeking for all claimants in 12 areas of Britain. A programme of evaluation accompanied the launch of the Jobcentre Plus Pathfinders. This work was designed to provide an early assessment of the Pathfinders, to identify good practice and inform the continuous improvement and future roll out of the service. This overview report has two principal aims. First, it brings together and reports the key findings of qualitative and quantitative evaluations of Jobcentre Plus services at Pathfinder sites that were carried out from October 2001 to May 2002. This was a period during which the implementation of Jobcentre Plus was obstructed by industrial action, a factor that needs to be taken into account when assessing early performance. The findings of this research are then related to comparable research on ONE. Second, it charts the changes made in the provision of Jobcentre Plus since its inception and identifies how Jobcentre Plus has progressed from the ONE service from which it developed

A search for starlight reflected from upsilon And's innermost planet

In data from three clear nights of a WHT/UES run in 2000 Oct/Nov, and using improved Doppler tomographic signal-analysis techniques, we have carried out a deep search for starlight reflected from the innermost of upsilon And's three planets. We place upper limits on the planet's radius R_p as functions of its projected orbital velocity K_p ~ 139 sin i km/sec for various assumptions about the wavelength-dependent geometric albedo spectrum p(\lambda) of its atmosphere. For a grey albedo p we find R_p \sqrt{p} < 0.98 R_Jup with 0.1 percent false-alarm probability (4-sigma). For a Sudarsky et al (2000) Class V model atmosphere, the mean albedo in our 380-676 nm bandpass is ~ 0.42, requiring R_p ~ 0.19 requires R_p < 2.23 R_Jup. The star's v sin{i} ~ 10 km/sec and estimated rotation period P_{rot} ~ 10 d suggest a high orbital inclination i ~ 70-80 degrees. We also develop methods for assessing the false-alarm probabilities of faint candidate detections, and for extracting information about the albedo spectrum and other planetary parameters from faint reflected-light signals.Comment: 20 pages, 20 Figures, accepted for publication in MNRA

Interpreting malaria age-prevalence and incidence curves: a simulation study of the effects of different types of heterogeneity

ABSTRACT: BACKGROUND: Individuals in a malaria endemic community differ from one another. Many of these differences, such as heterogeneities in transmission or treatment-seeking behaviour, affect malaria epidemiology. The different kinds of heterogeneity are likely to be correlated. Little is known about their impact on the shape of age-prevalence and incidence curves. In this study, the effects of heterogeneity in transmission, treatment-seeking and risk of co-morbidity were simulated. METHODS: Simple patterns of heterogeneity were incorporated into a comprehensive individual-based model of Plasmodium falciparum malaria epidemiology. The different types of heterogeneity were systematically simulated individually, and in independent and co-varying pairs. The effects on age-curves for parasite prevalence, uncomplicated and severe episodes, direct and indirect mortality and first-line treatments and hospital admissions were examined. RESULTS: Different heterogeneities affected different outcomes with large effects reserved for outcomes which are directly affected by the action of the heterogeneity rather than via feedback on acquired immunity or fever thresholds. Transmission heterogeneity affected the age-curves for all outcomes. The peak parasite prevalence was reduced and all age-incidence curves crossed those of the reference scenario with a lower incidence in younger children and higher in older age-groups. Heterogeneity in the probability of seeking treatment reduced the peak incidence of first-line treatment and hospital admissions. Heterogeneity in co-morbidity risk showed little overall effect, but high and low values cancelled out for outcomes directly affected by its action. Independently varying pairs of heterogeneities produced additive effects. More variable results were produced for co-varying heterogeneities, with striking differences compared to independent pairs for some outcomes which were affected by both heterogeneities individually. CONCLUSIONS: Different kinds of heterogeneity both have different effects and affect different outcomes. Patterns of co-variation are also important. Alongside the absolute levels of different factors affecting age-curves, patterns of heterogeneity should be considered when parameterizing or validating models, interpreting data and inferring from one outcome to anothe

Variation analysis and gene annotation of eight MHC haplotypes: The MHC Haplotype Project

The human major histocompatibility complex (MHC) is contained within about 4 Mb on the short arm of chromosome 6 and is recognised as the most variable region in the human genome. The primary aim of the MHC Haplotype Project was to provide a comprehensively annotated reference sequence of a single, human leukocyte antigen-homozygous MHC haplotype and to use it as a basis against which variations could be assessed from seven other similarly homozygous cell lines, representative of the most common MHC haplotypes in the European population. Comparison of the haplotype sequences, including four haplotypes not previously analysed, resulted in the identification of >44,000 variations, both substitutions and indels (insertions and deletions), which have been submitted to the dbSNP database. The gene annotation uncovered haplotype-specific differences and confirmed the presence of more than 300 loci, including over 160 protein-coding genes. Combined analysis of the variation and annotation datasets revealed 122 gene loci with coding substitutions of which 97 were non-synonymous. The haplotype (A3-B7-DR15; PGF cell line) designated as the new MHC reference sequence, has been incorporated into the human genome assembly (NCBI35 and subsequent builds), and constitutes the largest single-haplotype sequence of the human genome to date. The extensive variation and annotation data derived from the analysis of seven further haplotypes have been made publicly available and provide a framework and resource for future association studies of all MHC-associated diseases and transplant medicine

New evidence of factor structure and measurement invariance of the SDQ across five European nations

The main purpose of the present study was to test the internal structure and to study the measurement invariance of the Strength and Difficulties Questionnaire (SDQ), self-reported version, in five European countries. The sample consisted of 3012 adolescents aged between 12 and 17 years (M = 14.20; SD = 0.83). The five-factor model (with correlated errors added), and the five-factor model (with correlated errors added) with the reverse-worded items allowed to cross-load on the Prosocial subscale, displayed adequate goodness of-fit indices. Multi-group confirmatory factor analysis showed that the five-factor model had partial strong measurement invariance by countries. A total of 11 of the 25 items were non-invariant across samples. The level of internal consistency of the Total difficulties scores was .84, ranging between .69 and .78 for the SDQ subscales. The findings indicate that the SDQ's scales need to be modified in various ways for screening emotional and behavioural problems in the five European countries that were analyzed